A wide variety of IMDs that employ electronic circuitry for providing electrical stimulation of body tissue and/or monitoring a physiologic condition are known in the art. Such IMDs may deliver electrical therapy energy in the form of shocking energy and stimulating pulses to selected body tissue and typically comprise output circuitry for generating the electrical energy under prescribed conditions and at least one lead bearing a stimulation electrode for delivering the electrical energy to the selected tissue. For example, cardiac pacemakers and implantable cardioverter-defibrillators (ICDs) have been developed for maintaining a desired heart rate during episodes of bradycardia or for applying cardioversion or defibrillation therapies to the heart upon detection of serious arrhythmias. Other nerve, brain, muscle and organ tissue stimulating medical devices are also known for treating a variety of conditions.
Currently available IMDs, including ICDs and implantable pulse generators (IPGs), are typically formed having a metallic housing that is hermetically sealed and, therefore, is impervious to body fluids, a header or connector assembly mounted to the housing for making electrical and mechanical connection with one or more leads, and possess telemetry capabilities for communicating with external devices. Over the past 20 years, the IMDs have evolved from relatively bulky, crude, and short-lived devices to complex, long-lived, and miniaturized IMDs that are steadily being miniaturized with their functionality continuously increasing. For example, numerous improvements have been made in cardioversion/defibrillation leads and electrodes that have enabled the cardioversion/defibrillation energy to be precisely delivered about selected upper and lower heart chambers and thereby dramatically reducing the delivered shock energy required to cardiovert or defibrillate the heart chamber. Moreover, the high voltage output circuitry has been improved in many respects to provide monophasic, biphasic, or multi-phase cardioversion/defibrillation shock or pulse waveforms that are efficacious, sometimes with particular combinations of cardioversion/defibrillation electrodes, in lowering the required shock energy to cardiovert or defibrillate the heart.
The miniaturization of IMDs is driving size and cost reduction of all IMD components including the electronic circuitry components, where it is desirable to increase the density and reduce the size so that the overall circuitry can be more compact. As the dimensions of the IMDs decreases, the electronic circuits of the IMD circuitry are preferably formed as integrated circuits in order to fit within a minimal space. Furthermore, as the dimensions of the components are also shrinking, it is desirable to improve the use of the dimensions within the IMD package.
One response to this desire has been through technological improvements to the packaging for the dice in which the output circuitry is included through such packaging techniques as the reconstituted wafer packaging. In particular, development efforts in reconstituted wafer packaging, also known as fan out wafer level packaging, focus on producing thinner and smaller electronic packages. However, there are significant technical barriers to developing and packaging a versatile high voltage dice such as those used in the aforementioned IMDs. Accordingly, it is desirable to provide an improved reconstituted wafer level package and an improved reconstituted wafer level package for high voltage components.